This application proposes to study post-mortem human brains using semi quantitative in situ hybridization as a tool for examining the gene expression and regulation of several molecular elements thought to be relevant to mental illness. This level of analysis constitutes a useful intermediary between the basic molecular, anatomical, and regulatory studies that can be performed in animals (Projects I & II), and the more integrative but indirect studies performed in human subjects (Project IV). Since work in rats suffers from the absence of a convincing model of depression, and since work in humans suffers from the lack of direct access to the brain, these post-mortem studies afford the opportunity to examine directly the brains of mentally ill subjects in comparison to controls, and to profit from the growing body of information on the structure, tissue specific expression and regulatability of genes coding for neuropeptides, neurotransmitter synthetic enzymes and receptors which have been implicated in the major psychoses. However, post-mortem studies also carry a number of problems, including issues of variability due to post-mortem time, the effect of medications and the need for appropriate controls which require careful consideration. An advantage afforded by in situ hybridization is the relative stability of most mRNA levels which may require hours to days to be significantly affected by cellular events. Thus, significant alterations in these levels are likely to reflect long-term, sustained influences as opposed to the events immediately preceding death. This application is aimed at the study of stress-axis related messages (e.g. secretagogues, corticosteroid receptors) and serotonin related messages in conjunction with suicide and depression. However, given the paucity of information currently available on the expression of most of these genes in human brains, a large portion of our effort will be aimed at describing and characterizing the above systems in normal (non-psychiatric) human brains. The information so derived should be intrinsically valuable as well as serving as the backdrop for studying psychiatrically relevant brains. We shall then study the relevant messages in brains from suicides and their appropriate controls. This will entail qualitative and quantitative analysis of the expression of specific genes in their anatomical context. It will also involve the simultaneous analysis of multiple, interrelated genes within a particular brain, in an attempt to reconstruct the regulatory tone of entire system (e.g. measuring corticosteroid receptor mRNAs, secretagogue mRNA, proopiomelanocortin mRNA, and 5-HT receptors mRNAs in suicide brains) and to compare it to the status in the control brains. The sources of tissue have been identified and the feasibility of the studies has been tested. Current plans involve multiple studies of suicides varying in terms of age, post mortem and ability to ascertain psychiatric status.